1. Field of the Invention
The invention relates to a preparation for shrinkproofing wool.
2. Description of the Prior Art
It is well known that, in the untreated state, wool shrinks and felts when it is laundered in aqueous liquors. In order to counteract this shrinking and felting, chemical treatments have already been recommended, in which the structure of the wool is changed or in which finishes are used, which contain resin that is deposited on and envelopes the wool fiber. However, both processes produce products having a hand which is regarded as unpleasant by the user.
The reduction of the shrinkage of wool on laundering by treatment with organosilicone compounds has also already been recommended. Such processes are described in British Pat. Nos. 594,901, 613,267 and 629,329. In accordance with these processes, the wool is treated with certain silanes.
In British Pat. No. 746,307, a process for preventing shrinkage of wool is described wherein the wool fibers are finished with certain organopolysiloxanes. Admittedly, some degree of shrinkproofness is achieved with this process. However, this effect is not washfast.
In a further series of publications, for example, in German Offenlegungsschriften Nos. 2,242,297, 2,335,751 and 2,523,270, processes for shrinkproofing keratin fibers by the application of organopolysiloxanes are disclosed. An essential characteristic of these processes is the amino group content of these compounds.
For example, the process according to German Offenlegungsschrift No. 2,242,297 is characterized by the fact that, as organopolysiloxanes, those with units of the general formula ##EQU1## are used, in which n has an average value of 1.9 to 2.1 and
R represents an organic residue, which is linked to silicon by a silicon-carbon bond, 0.25 to 50% of the R substituents being monovalent residues, which have fewer than 30 carbon atoms and, at a distance of at least three carbon atoms from the silicon atom, contain at least one imino group and at least one primary or secondary amino group --NX.sub.2, in which X is a hydrogen atom, an alkyl group with 1 to 30 carbon atoms or an aryl group, PA1 0.03 to 3 mole percent of mercaptoalkyl or mercaptoaryl residues, PA1 0.06 to 6 mole percent of aminoalkyl residues, and PA1 0.1 to 10 mole percent of anionic groups, which are linked to silicon atoms through carbon atoms, PA1 0.3 to 3 mole percent of mercaptoalkyl or mercaptoaryl residues, PA1 0.06 to 6 mole percent of aminoalkyl residues, or PA1 0.1 to 10 mole percent of anionic groups, which are linked to silicon atoms over carbon atoms PA1 Z is a hydrogen residue, a monovalent alkyl or aryl residue, an acyl residue or a trimethylsilyl residue, PA1 n has a value of 2 to 3 and PA1 x has a value of 2 to 80. PA1 Y is the ##STR1## or the trimethylsilyl residue, and y has a value of 4 to 20. PA1 X is a --O.sup.- residue or the --OR.sup.4 group. At the same time, R.sup.4 is a hydrogen residue or an alkyl residue with 1 to 4 carbon atoms. These anionic residues may be present in the form of the free acid or they may be completely or partially neutralized.
and the remaining R substituents being monovalent hydrocarbon residues, carboxyalkyl residues, or cyanalkyl residues with 1 to 30 carbon atoms, at least 70% of which consist of monovalent hydrocarbon residues with 1 to 18 carbon atoms.
From German Offenlegungsschrift 2,335,751, a process for treating keratin fibers is known, which is characterized by the fact that the organopolysiloxane composition contains the product which is obtained by mixing components (A) and (B) wherein:
(A) is a polydiorganosiloxane with terminal hydroxyl groups linked to silicon atoms and a molecular weight of at least 750, in which at least 50% of the organic substituents of the polydiorganosiloxane are methyl groups and in which the other substituents are monovalent hydrocarbon groups with 2 to 30 carbon atoms and
(B) is an organosilane of the general formula EQU RSiR'.sub.n X.sub.3-n
in which
R is a monovalent group composed of carbon, hydrogen, nitrogen, and possibly oxygen, contains at least 2 amino groups and is linked by a silicon-carbon to silicon,
R' is an alkyl group or an aryl group,
X represents alkoxy groups with 1 to 4 carbon atoms inclusive and
n is 0 or 1, and/or a partial hydrolysate and condensate of the organosilane.
In this German Offenlegungsschrift, it is stated that the two components of the mixture should be reacted, if they are to be applied from an aqueous medium.
In practice, however, it is not possible to prepare stable aqueous emulsions from such reaction products. Gel-like reaction products are formed which cannot be converted into an emulsion. They are therefore not suitable for shrink-proofing wool.
If these reaction products are used in the form of organic solutions, the effect achieved is too small for practical purposes. Moreover, after a period of time, a siloxane gel precipitates from the solvent-containing liquor as a result of the action of the moisture of the atmosphere and obstructs the equipment used for treating the wool.
In the "Journal of Textile Institute" 68 (1977), 163 ff., preparations for shrinkproofing wool are described which contain polysiloxanes in which polyether chains are linked to the molecule. These preparations do not produce a satisfactory effect. Moreover, the high temperatures of 120.degree. C. and the long reaction times of 60 minutes which are required for fixing these compounds on the wool fibers, may, in themselves, cause considerable damage to and discoloration of the wool.
Furthermore, from German Offenlegunsschrift No. 1,769,249 a process for treating fiber material, for example, wool, is known in which organosiloxanes, which contain mercaptopropyl groups, are used in the form of an emulsion. With these compounds, however, it is only possible to improve the soil repellency. The compounds are not suitable for making wool shrinkproof. Consequently, these prior art preparations have not provided fully satisfactory means for shrinkproof finishing of wool.